Closure implants (aka occlusion devices) for closing the left arterial appendage are described, for example, in Tischler et al., US Published Application No. 2014/0135817, Sutton et al., US Published Application No. 2003/0181942 and Clark et al., US Published Application No. 2013/0138138. These applications seek to respectively provide an occlusion device that controls thrombus formation within the left atrial appendage, a delivery system that provides for delivery through geometrically complex vascular paths, and an occlusion device with improved circumferential strength and without foreshortening or excessive distortion.
Each of these systems mentioned in the previous paragraph includes a self-expanding support frame. Self-expanding systems of this kind are generally based on what is known as the pull-back principle, in which an outer catheter sleeve forces the implant into a collapsed form and releases it again by retraction of the outer sleeve. Due to the shaping of the closure implants (usually barrel-shaped), the release cannot be controlled as accurately by the pull-back principle, since the closure implant can spring out suddenly when released to an extent of approximately two thirds. Since the atrial appendage is an extremely fragile tissue, there is a high risk of injury by an uncontrolled release of a closure implant.
According to FIG. 1 the current systems and closure implants 1c are also firmly connected by a screw 1b and in particular a guide wire to the catheter 1a. This hinders the checking of successful placement insofar as the fixing of the implant in the atrial appendage tissue cannot be sufficiently examined (for example a secure fit of the implant after placement in the atrial appendage can be determined on the basis of a pull test).